[Development] Rotating JPEG images by default

[Gunnar Sletta]

> On 23 Apr 2015, at 13:20, Alberto Mardegan <mardy at users.sourceforge.net> wrote:
> 
> On 04/23/2015 01:36 PM, Gunnar Sletta wrote:
>> I think we should strive to not introduce regressions on purpose. Hence:
>>  - Revert the behavioral change in 5.4 which adds rotation to JPEGs
>>  - Have opt-in rotation in QImageReader.
>>  - Keep TIFF rotation as it is (and change it to the Qt-wide default for Qt 6)
>> 
>> Anything else will cause us a lot of pain down the line.
> 
> Also the above causes some pain. Whether we go for opt-in or opt-out of 
> the automatic rotation, please have a static method to globally specify 
> whether automatic rotation is desired or not.

I don’t think static options like that are a very good idea. It is not hard to enable an option in your image reading code after all. And it will be in the part of the code where people normally look for image stuff. If we put it in QGuiApplication, nobody would know to look for it there.

> We should have QML Image show the JPEGs with the correct rotation 
> without requiring special flags or custom image readers.

Whether or not Image {} sets the rotation mode is a separate feature, but following the same logic. Image should NOT rotate by default. Image::respectFileOrientation or whatever as an opt-in would be perfectly fine. Again, we can talk about changing that default for Qt 6, but not in the 5 timeframe, IMO.

> 
> Ciao,
>   Alberto
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